Bump regex from 2026.4.4 to 2026.5.9 (#104)

Bumps [regex](https://github.com/mrabarnett/mrab-regex) from 2026.4.4 to 2026.5.9.
- [Changelog](https://github.com/mrabarnett/mrab-regex/blob/hg/changelog.txt)
- [Commits](mrabarnett/mrab-regex@2026.4.4...2026.5.9)

---
updated-dependencies:
- dependency-name: regex
  dependency-version: 2026.5.9
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pyproject.toml

@@ -8,7 +8,7 @@ readme = "README.md"
 requires-python = ">=3.10, < 4.0"
 
 dependencies = [
-    "regex>=2025.0,<2027.0",
+    "regex>=2026.5.9,<2027.0",
     "httpx >= 0.28, < 1.0",
     "pydantic>=2.13.3,<3.0",
     "textual>=8.2.4",